1. Field of the Invention
The invention relates to an image forming apparatus of electronic photograph form, specially relates to an image forming apparatus capable of obtaining characteristic of high gradient through a subline control.
2. Related Background Art
In recent years, in image forming apparatus, in order to get an output image with high resolution, it is strongly required to realize high gradient. Further, it also is required to realize miniaturization of apparatus and low cost. For example, in patent document 1, in order to realize high gradient, such technology of the subline control is disclosed to drive a corresponding light source on/off several times through combining different time interval when forming one pixel.
Patent document 1: Japan patent publication H09-136449.
However, in the conventional technology stated above, with high gradient, a number of lines (subline) increases. As a result, there are such problems that circuit scale becomes large and it is impossible to realize the miniaturization of apparatus and the low cost.